With the big day only one week away, federal officials are warning the public to be on the lookout for the lenses, which they say can cause permanent damage to the eyes.

It's illegal to buy or sell contact lenses of any kind without a prescription from an ophthalmologist, optometrist or licensed optician.

Officials say the lenses are often sold in Halloween or novelty shops, salons, beauty supply stores, or online, never requiring a prescription.

While many of them sell for as little as $20, the vendors are not authorized distributors, officials say.

The effort to seize the lenses involves the Food and Drug Administration’s (FDA) Office of Criminal Investigations (OCI), U.S. Immigration and Customs Enforcement’s (ICE) Homeland Security Investigations (HSI) and U.S. Customs and Border Protection (CBP).

"Even though Halloween approaches, consumers shouldn't let a good deal or great costume blind them to the dangers of counterfeit decorative contact lenses," said HSI Executive Associate Director James Dinkins in a statement. "What's truly scary is the damage these counterfeit lenses can do to your eyes for a lifetime."